/*
Copyright 2021 - 2023 The Matrix.org Foundation C.I.C.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

import { Optional } from "matrix-events-sdk";
import React, { useContext, useEffect, useRef, useState } from "react";
import { EventTimelineSet, Room, Thread } from "matrix-js-sdk/src/matrix";

import BaseCard from "../views/right_panel/BaseCard";
import ResizeNotifier from "../../utils/ResizeNotifier";
import MatrixClientContext from "../../contexts/MatrixClientContext";
import { _t } from "../../languageHandler";
import { ContextMenuButton } from "../../accessibility/context_menu/ContextMenuButton";
import ContextMenu, { ChevronFace, MenuItemRadio, useContextMenu } from "./ContextMenu";
import RoomContext, { TimelineRenderingType } from "../../contexts/RoomContext";
import TimelinePanel from "./TimelinePanel";
import { Layout } from "../../settings/enums/Layout";
import { RoomPermalinkCreator } from "../../utils/permalinks/Permalinks";
import Measured from "../views/elements/Measured";
import PosthogTrackers from "../../PosthogTrackers";
import { ButtonEvent } from "../views/elements/AccessibleButton";
import Spinner from "../views/elements/Spinner";
import Heading from "../views/typography/Heading";

interface IProps {
    roomId: string;
    onClose: () => void;
    resizeNotifier: ResizeNotifier;
    permalinkCreator: RoomPermalinkCreator;
}

export enum ThreadFilterType {
    "My",
    "All",
}

type ThreadPanelHeaderOption = {
    label: string;
    description: string;
    key: ThreadFilterType;
};

export const ThreadPanelHeaderFilterOptionItem: React.FC<
    ThreadPanelHeaderOption & {
        onClick: () => void;
        isSelected: boolean;
    }
> = ({ label, description, onClick, isSelected }) => {
    return (
        <MenuItemRadio active={isSelected} className="mx_ThreadPanel_Header_FilterOptionItem" onClick={onClick}>
            <span>{label}</span>
            <span>{description}</span>
        </MenuItemRadio>
    );
};

export const ThreadPanelHeader: React.FC<{
    filterOption: ThreadFilterType;
    setFilterOption: (filterOption: ThreadFilterType) => void;
    empty: boolean;
}> = ({ filterOption, setFilterOption, empty }) => {
    const [menuDisplayed, button, openMenu, closeMenu] = useContextMenu<HTMLElement>();
    const options: readonly ThreadPanelHeaderOption[] = [
        {
            label: _t("All threads"),
            description: _t("Shows all threads from current room"),
            key: ThreadFilterType.All,
        },
        {
            label: _t("My threads"),
            description: _t("Shows all threads you've participated in"),
            key: ThreadFilterType.My,
        },
    ];

    const value = options.find((option) => option.key === filterOption);
    const contextMenuOptions = options.map((opt) => (
        <ThreadPanelHeaderFilterOptionItem
            key={opt.key}
            label={opt.label}
            description={opt.description}
            onClick={() => {
                setFilterOption(opt.key);
                closeMenu();
            }}
            isSelected={opt === value}
        />
    ));
    const contextMenu = menuDisplayed ? (
        <ContextMenu
            top={108}
            right={33}
            onFinished={closeMenu}
            chevronFace={ChevronFace.Top}
            wrapperClassName="mx_BaseCard_header_title"
        >
            {contextMenuOptions}
        </ContextMenu>
    ) : null;
    return (
        <div className="mx_BaseCard_header_title">
            <Heading size="4" className="mx_BaseCard_header_title_heading">
                {_t("Threads")}
            </Heading>
            {!empty && (
                <>
                    <ContextMenuButton
                        className="mx_ThreadPanel_dropdown"
                        inputRef={button}
                        isExpanded={menuDisplayed}
                        onClick={(ev: ButtonEvent) => {
                            openMenu();
                            PosthogTrackers.trackInteraction("WebRightPanelThreadPanelFilterDropdown", ev);
                        }}
                    >
                        {`${_t("Show:")} ${value?.label}`}
                    </ContextMenuButton>
                    {contextMenu}
                </>
            )}
        </div>
    );
};

interface EmptyThreadIProps {
    hasThreads: boolean;
    filterOption: ThreadFilterType;
    showAllThreadsCallback: () => void;
}

const EmptyThread: React.FC<EmptyThreadIProps> = ({ hasThreads, filterOption, showAllThreadsCallback }) => {
    let body: JSX.Element;
    if (hasThreads) {
        body = (
            <>
                <p>
                    {_t(
                        "Reply to an ongoing thread or use “%(replyInThread)s” " +
                            "when hovering over a message to start a new one.",
                        {
                            replyInThread: _t("Reply in thread"),
                        },
                    )}
                </p>
                <p>
                    {/* Always display that paragraph to prevent layout shift when hiding the button */}
                    {filterOption === ThreadFilterType.My ? (
                        <button onClick={showAllThreadsCallback}>{_t("Show all threads")}</button>
                    ) : (
                        <>&nbsp;</>
                    )}
                </p>
            </>
        );
    } else {
        body = (
            <>
                <p>{_t("Threads help keep your conversations on-topic and easy to track.")}</p>
                <p className="mx_ThreadPanel_empty_tip">
                    {_t(
                        "<b>Tip:</b> Use “%(replyInThread)s” when hovering over a message.",
                        {
                            replyInThread: _t("Reply in thread"),
                        },
                        {
                            b: (sub) => <b>{sub}</b>,
                        },
                    )}
                </p>
            </>
        );
    }

    return (
        <aside className="mx_ThreadPanel_empty">
            <div className="mx_ThreadPanel_largeIcon" />
            <h2>{_t("Keep discussions organised with threads")}</h2>
            {body}
        </aside>
    );
};

const ThreadPanel: React.FC<IProps> = ({ roomId, onClose, permalinkCreator }) => {
    const mxClient = useContext(MatrixClientContext);
    const roomContext = useContext(RoomContext);
    const timelinePanel = useRef<TimelinePanel | null>(null);
    const card = useRef<HTMLDivElement | null>(null);

    const [filterOption, setFilterOption] = useState<ThreadFilterType>(ThreadFilterType.All);
    const [room, setRoom] = useState<Room | null>(null);
    const [narrow, setNarrow] = useState<boolean>(false);

    const timelineSet: Optional<EventTimelineSet> =
        filterOption === ThreadFilterType.My ? room?.threadsTimelineSets[1] : room?.threadsTimelineSets[0];
    const hasThreads = Boolean(room?.threadsTimelineSets?.[0]?.getLiveTimeline()?.getEvents()?.length);

    useEffect(() => {
        const room = mxClient.getRoom(roomId);
        room?.createThreadsTimelineSets()
            .then(() => room.fetchRoomThreads())
            .then(() => {
                setFilterOption(ThreadFilterType.All);
                setRoom(room);
            });
    }, [mxClient, roomId]);

    useEffect(() => {
        if (timelineSet && !Thread.hasServerSideSupport) {
            timelinePanel.current?.refreshTimeline();
        }
    }, [timelineSet, timelinePanel]);

    return (
        <RoomContext.Provider
            value={{
                ...roomContext,
                timelineRenderingType: TimelineRenderingType.ThreadsList,
                showHiddenEvents: true,
                narrow,
            }}
        >
            <BaseCard
                header={
                    <ThreadPanelHeader
                        filterOption={filterOption}
                        setFilterOption={setFilterOption}
                        empty={!hasThreads}
                    />
                }
                className="mx_ThreadPanel"
                onClose={onClose}
                withoutScrollContainer={true}
                ref={card}
            >
                {card.current && <Measured sensor={card.current} onMeasurement={setNarrow} />}
                {timelineSet ? (
                    <TimelinePanel
                        key={filterOption + ":" + (timelineSet.getFilter()?.filterId ?? roomId)}
                        ref={timelinePanel}
                        showReadReceipts={false} // No RR support in thread's list
                        manageReadReceipts={false} // No RR support in thread's list
                        manageReadMarkers={false} // No RM support in thread's list
                        sendReadReceiptOnLoad={false} // No RR support in thread's list
                        timelineSet={timelineSet}
                        showUrlPreview={false} // No URL previews at the threads list level
                        empty={
                            <EmptyThread
                                hasThreads={hasThreads}
                                filterOption={filterOption}
                                showAllThreadsCallback={() => setFilterOption(ThreadFilterType.All)}
                            />
                        }
                        alwaysShowTimestamps={true}
                        layout={Layout.Group}
                        hideThreadedMessages={false}
                        hidden={false}
                        showReactions={false}
                        className="mx_RoomView_messagePanel"
                        membersLoaded={true}
                        permalinkCreator={permalinkCreator}
                        disableGrouping={true}
                    />
                ) : (
                    <div className="mx_AutoHideScrollbar">
                        <Spinner />
                    </div>
                )}
            </BaseCard>
        </RoomContext.Provider>
    );
};
export default ThreadPanel;
